Separator for flat-type polyelectrolyte fuel cell and polyelectrolyte fuel cell employing that separator

ABSTRACT

A separator having a separator member coupled body having a metal plate as a base body, and formed by integrally coupling a plurality of separator members each having through holes for feeding fuel to an electrolyte of the fuel cell, said through holes arranged so as to correspond to the unit cell and to be perpendicular to a surface of said base body, and frame coupled bodies each made of an insulating material, each having openings for fuel feeding or oxygen feeding corresponding to the respective separator members, and each formed by integrally coupling a plurality of frame portions that give insulation between the unit cells, wherein said frame coupled bodies, making a pair, sandwich said separator member coupled body from its both sides, and each frame portion of one of said frame coupled bodies is capable of fitting a membrane electrode assembly (MEA) of the fuel cell into the opening.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/477,600filed Nov. 13, 2003 (now patented as U.S. Pat. No. 7,316,856) whichclaims the benefit of PCT/JP 03/05936 filed May 13, 2003 and JapanesePatent Application No. 2002-140202 filed May 15, 2002, the entirecontents of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a fuel cell and, in particular, relatesto a separator for a flat-type polymer electrolyte fuel cell, and apolymer electrolyte fuel cell using such a separator.

BACKGROUND ART

A fuel cell is a device wherein fuel (reducing agent) and oxygen or air(oxidizing agent) are continuously supplied from the exterior to bereacted electrochemically, thereby to produce electrical energy, andfuel cells are classified based on their operating temperatures, kindsof using fuel, applications and so forth. On the other hand, recently,they are, in general, roughly classified into five kinds, i.e. a solidoxide fuel cell, a molten carbonate fuel cell, a phosphoric acid fuelcell, a polymer electrolyte fuel cell, and an alkaline aqueous solutionfuel cell, mainly depending on kinds of using electrolytes.

These fuel cells are of the type using hydrogen gas produced frommethane etc. as fuel. Recently, however, there is also known a directmethanol fuel cell (hereinafter also referred to as DMFC) wherein amethanol aqueous solution is directly used as fuel.

Among them, attention has been paid to a solid polymer fuel cell(hereinafter also referred to as PEFC) having a structure wherein asolid polymer membrane is sandwiched between two kinds of electrodes,and further, these members are sandwiched between separators.

In general, this PEFC is in the form of a stack structure wherein aplurality of unit cells each having electrodes arranged on both sides ofa solid polymer membrane, respectively, are stacked so as to increase anelectromotive force thereof depending on the purpose. A separatordisposed between the unit cells is generally formed on one side thereofwith a fuel gas feed groove for feeding fuel gas to one of the adjacentunit cells. In case of such a separator, fuel gas and oxidant gas aresupplied along the surfaces of the separator.

As the PEFC separators, there are known a separator obtained by planninga graphite board and applying a grooving process thereto, a moldedseparator of a carbon compound obtained by kneading carbon into resin, ametal separator applied with a grooving process by etching or the like,a separator wherein the surface of a metal material is coated withanticorrosive resin, and so forth. These separators are each formed witha fuel gas feed groove and/or an oxidant gas feed groove according torequirements.

Like a fuel cell for a portable terminal, for example, there are alsothose instances where an electromotive force is not required so much,but it is required to be of the flat type and as thin as possible, otherthan the fuel cell of the stack structure. However, there has also beena problem that the feeding of fuel and oxygen becomes uneven dependingon places in case of the flat type wherein a plurality of unit cells arearranged in a flat manner and electrically connected in series.

In view of this, for improving this unevenness of the fuel feeding,there has been considered a separator having a structure wherein manythrough holes are formed in a perpendicular direction relative to asurface of the separator contacting a membrane electrode assembly (MEA),and fuel and oxygen are fed via the through holes.

Herein, an assembly including electrode portions located between afuel-feed-side separator of a fuel cell and an oxygen-feed-sideseparator thereof, for example, an assembly such as a membrane composedof a collector layer, a fuel electrode, a polymer electrolyte, an oxygenelectrode, and a collector layer that are stacked in the order named, iscalled a membrane electrode assembly (MEA).

However, if the separator having the foregoing structure is formed, forexample, only from a metal material, it is necessary to increase athickness of the separator in view of strength so that reduction inweight of a fuel cell becomes difficult.

As described above, in recent years, the possibility has been increasedfor the fuel cells to be widely used and, in case of the PEFC, there hasalso been required such a one that is of the flat type and as thin aspossible. However, with respect to the separator, sufficient strengthand further reduction in weight have been required, and further, therehas been required such a one that has a sealing function for preventingfuel, moisture etc. inside a cell from leaking out to the exterior ofthe cell from portions other than a fuel feed surface when it isemployed in a polymer electrolyte fuel cell.

DISCLOSURE OF THE INVENTION

The present invention copes with them and provides a separator that canensure a strength required for the separator and deal with furtherreduction in weight, and further provides a separator that has a sealingfunction for preventing fuel, moisture etc. inside a cell from leakingout to the exterior of the cell from portions other than a fuel feedsurface when it is employed in a polymer electrolyte fuel cell, inaddition to ensuring the strength required for the separator and thefurther reduction in weight.

Simultaneously, using such a separator and utilizing a conventionalfront-back connecting method for a double-sided printed wiring board, itaims to realize a polymer electrolyte fuel cell in which unit cells canbe easily and simply connected to each other and which enables reductionin weight and improvement in strength.

For accomplishing these objects, the present invention is configuredsuch that a separator for a flat-type polymer electrolyte fuel cellhaving unit cells arranged in a flat manner, which is provided on a fuelfeed side or an oxygen feed side, comprises a separator member coupledbody having a metal plate as a base body, and formed by integrallycoupling a plurality of separator members each having through holes forfeeding fuel to an electrolyte of the fuel cell, said through holesarranged so as to correspond to the unit cell and to be perpendicular toa surface of said base body, and frame coupled bodies each made of aninsulating material, each having openings for fuel feeding or oxygenfeeding corresponding to the respective separator members, and eachformed by integrally coupling a plurality of frame members that giveinsulation between the unit cells, wherein said frame coupled bodies,making a pair, sandwich said separator member coupled body from its bothsides, and each frame member of one of the frame coupled bodies on thefront and back of said separator member coupled body is capable offitting a membrane electrode assembly (MEA) of the fuel cell into saidopening.

Further, the present invention is configured such that a separator for aflat-type polymer electrolyte fuel cell having unit cells arranged in aflat manner, which is provided on a fuel feed side or an oxygen feedside, comprises a separator member coupled body having a metal plate asa base body, and formed by integrally coupling a plurality of separatormembers each having through holes for feeding fuel to an electrolyte ofthe fuel cell, said through holes arranged so as to correspond to theunit cell and to be perpendicular to a surface of said base body, aframe coupled body made of an insulating material, having openings forfuel feeding or oxygen feeding corresponding to the respective separatormembers, and formed by integrally coupling a plurality of frame membersthat give insulation between the unit cells, and a solid plate membermade of an insulating material, or a stacked base member composed of asolid plate member made of an insulating material and a conductive layerstacked thereon, wherein said frame coupled body and said solid platemember or said stacked base member, making a pair, sandwich saidseparator member coupled body from its both sides, and each frame memberof said frame coupled body is capable of fitting a membrane electrodeassembly (MEA) of the fuel cell into said opening.

As described before, in the present invention, an assembly includingelectrode portions located between a fuel-feed-side separator of a fuelcell and an oxygen-feed-side separator thereof, such as a membranecomposed of a collector layer, a fuel electrode, a polymer electrolyte,an oxygen electrode, and a collector layer that are stacked in the ordernamed, is called a membrane electrode assembly (MEA).

Being thus configured, the foregoing separator for the flat-type polymerelectrolyte fuel cell of the present invention is capable of providing aseparator that can ensure a strength required as the separator, and candeal with further reduction in weight. Further, by providing sealingmembers, it is possible to provide a separator that has a sealingfunction for preventing fuel, moisture etc. inside the respective unitcells from leaking out to the exterior of the cells from portions otherthan fuel feed surfaces when it is employed in the polymer electrolytefuel cell, in addition to ensuring the strength required for theseparator and the further reduction in weight.

Further, the present invention is configured so as to be a flat-typepolymer electrolyte fuel cell having unit cells arranged in a flatmanner, wherein a set of separators each having a separator membercoupled body and a pair of frame coupled bodies arranged so as tosandwich said separator member coupled body from its both sides,confront each other via membrane electrode assemblies (MEAs) of the fuelcell, and said membrane electrode assemblies (MEAs) are fitted intoopenings at confronting surfaces of said frame coupled bodies, saidseparator member coupled body has a metal plate as a base body, and isformed by integrally coupling a plurality of separator members eachhaving through holes for feeding fuel to an electrolyte of the fuelcell, said through holes arranged so as to correspond to the unit celland to be perpendicular to a surface of said base body, and said framecoupled bodies are each made of an insulating material, each having saidopenings for fuel feeding or oxygen feeding corresponding to therespective separator members, and each formed by integrally coupling aplurality of frame members that give insulation between the unit cells.

Further, the present invention is configured so as to be a flat-typepolymer electrolyte fuel cell having unit cells arranged in a flatmanner, wherein a set of separators each having a separator membercoupled body, a frame coupled body disposed on one side and a solidplate member made of an insulating material or a stacked base membercomposed of a solid plate member made of an insulating material and aconductive layer stacked thereon, disposed on the other side so as tosandwich said separator member coupled body therebetween, confront eachother via membrane electrode assemblies (MEAs) of the fuel cell, andsaid membrane electrode assemblies (MEAs) are fitted into openings ofsaid frame coupled body, said separator member coupled body has a metalplate as a base body, and is formed by integrally coupling a pluralityof separator members each having through holes for feeding fuel to anelectrolyte of the fuel cell, said through holes arranged so as tocorrespond to the unit cell and to be perpendicular to a surface of saidbase body, and said frame coupled body is made of an insulatingmaterial, has said openings for fuel feeding or oxygen feedingcorresponding to the respective separator members, and is formed byintegrally coupling a plurality of frame members that give insulationbetween the unit cells.

Being thus configured, the polymer electrolyte fuel cell of the presentinvention makes it possible to easily and simply connect the unit cellsto each other, and realize reduction in weight and improvement instrength in the flat-type PEFC, utilizing the conventional front-backconnecting method for a double-sided printed wiring board.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1( a) is a plan view showing a first example of an embodiment of aseparator for a flat-type polymer electrolyte fuel cell of the presentinvention, FIG. 1( b) is a sectional view taken along A1-A2 in FIG. 1(a), and FIG. 1( c) is a sectional view taken along A3-A4-A5-A6 in FIG.1( a).

FIG. 2( a) is a plan view wherein a frame coupled body in FIG. 1 is seenfrom a side A9 of FIG. 1( b), FIG. 2( b) is a plan view wherein aseparator member coupled body in FIG. 1 is seen from the side A9 of FIG.1( b), and FIG. 2( c) is a plan view wherein a frame coupled body inFIG. 1 is seen from the side A9 of FIG. 1( b).

FIG. 3( a) is a plan view showing a first mode example of a separatormember coupled body, FIG. 3( b) is a sectional view taken along B1-B2 ofFIG. 3( a), and FIG. 3( c) is a sectional view taken along B3-B4 of FIG.3( a).

FIG. 4 is a sectional view showing a second example of an embodiment ofa separator for a flat-type polymer electrolyte fuel cell of the presentinvention.

FIG. 5( a) is a sectional view showing a third example of an embodimentof a separator for a flat-type polymer electrolyte fuel cell of thepresent invention, and FIG. 5( b) is another sectional view of the thirdexample.

FIG. 6( a) is a sectional view of one example of an embodiment of apolymer electrolyte fuel cell of the present invention and is asectional view in a C1-C2 section shown in FIG. 6( b), FIG. 6( b) is abird's eye view of the polymer electrolyte fuel cell shown in FIG. 6(a), and FIG. 6( c) is a sectional view showing a wiring state in aC3-C4-C5-C6-C7 section shown in FIG. 6( b).

FIG. 7 is a sectional view of a fuel cell showing the state wherein ahousing is provided.

FIG. 8 is a process diagram of a fabricating method of the fuel cellshown in FIG. 6.

FIG. 9( c) is a sectional view of a first modification of the fuel cellshown in FIG. 6, and FIGS. 9( a) to 9(c) are fabrication processdiagrams of the fuel cell of the first modification.

FIG. 10( d) is a sectional view of a second modification of the fuelcell shown in FIG. 6, and FIGS. 10( a) to 10(d) are fabrication processdiagrams of the fuel cell of the second modification.

FIG. 11 is a diagram showing respective members in FIG. 1( a) by spacingpositions thereof apart from each other.

FIG. 12 is a diagram showing respective members in FIG. 4 by spacingpositions thereof apart from each other.

FIG. 13( a) is a plan view showing a fourth example of an embodiment ofa separator for a flat-type polymer electrolyte fuel cell of the presentinvention, and FIG. 13( b) is a diagram of an F1-F2 section in FIG. 13(a).

FIG. 14 is a sectional view of a polymer electrolyte fuel cell of thepresent invention using the separator of the fourth example shown inFIG. 13.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, embodiments of the present invention will be described.

In FIGS. 1 to 14, 10 denotes a separator member coupled body, 10A and10B each denote such ones (also referred to as a separator group) thatare in the state where a separator member coupled body is divided forrespective cells, 10 a and 10 b denote separator members, 11 denotes aseparator member coupled body, 11 a and 11 b denote separator members,12, 12A, 12B, 13, 13A, and 13B denote frame coupled bodies, 12 a denotesa frame member, 12 b denotes an opening, 12 c denotes a projectingportion, 13 a denotes a frame member, 13 b denotes an opening, 13 cdenotes a projecting portion, 15 denotes a through hole, 16 denotes anintercell separation through hole, 17 denotes a groove portion, 17 adenotes a fuel feed groove or an oxygen feed groove, 18 a and 18 bdenote sealing members, 20, 21, and 22 denote separators, 20 a, 21 a,and 22 a denote separators, 30 denotes a membrane electrode assembly(MEA), 40 denotes a fuel cell, 41 and 42 denote filled via portions, 41a denotes a through hole (through hole for connection betweenseparators), 42 b denotes a through hole (through hole for connectionbetween wiring-separator), 43 and 43 a denote wiring, 45 and 45A denotethrough holes, 46 and 46A denote hole portions, 50 denotes a housing, 61denotes copper foil, 61 a denotes wiring, 62 and 63 denote bumps, 65denotes copper foil, 70 denotes a plating portion, 110 denotes aseparator member coupled body, 112, 112A, and 112B denote solid platemembers, 112 c denotes a projecting portion, 113 a denotes a framemember, 113 b denotes an opening, 113, 113A, and 113B denote framecoupled bodies, 115 denotes a through hole, 120, 121, 122, 125, 126, and127 denote separators, and 130 denotes a conductive layer (copper foil).

A0 in FIG. 1( a) and B0 in FIG. 3 represent unit cell regions,respectively.

Further, A7 and A8 in FIGS. 2, 11 and 12, and B7 and B8 in FIG. 3represent joining portions (also referred to as coupling portions).

First, a first example of an embodiment of a separator for a flat-typepolymer electrolyte fuel cell of the present invention will be describedbased on FIGS. 1, 2 and 11.

A separator 20 of the first example is a separator that is disposed on afuel feed side or an oxygen feed side of the flat-type polymerelectrolyte fuel cell in which unit cells are arranged in a flat manner.This separator 20 is fed with fuel or oxygen in a directionperpendicular to the separator, and is a separator for fabricating afuel cell provided with two unit cells.

The foregoing separator 20 has a separator member coupled body 10 havinga metal plate as a base body, and frame coupled bodies 12 and 13 thatare arranged on front and back sides of the separator member coupledbody 10 so as to sandwich the separator member coupled body 10therebetween.

The separator member coupled body 10 comprises a plurality of separatormembers corresponding to unit cells, i.e. two separator members 10 a and10 b in the shown example, which are integrally coupled to each other.This separator member coupled body 10 is formed with a plurality ofthrough holes 15, corresponding to the unit cells, for feeding fuel toan electrolyte of the fuel cell, which are arranged so as to beperpendicular to the surface of the separator member coupled body.

On the other hand, each of the frame coupled bodies 12 and 13 is made ofan insulating material, and comprises frame members 12 a or 13 a forgiving insulation between the unit cells, which are integrally coupledto each other. Each of the frame coupled bodies 12 and 13 has openings12 b or 13 b for fuel feeding or oxygen feeding, corresponding to theseparator members 10 a and 10 b, respectively.

Upon stacking the frame coupled body 12, the separator member coupledbody 10, and the frame coupled body 13 to fabricate the separator 20, aprojecting portion 12 c (see FIG. 2( a)) of the frame coupled body 12and a projecting portion 13 c (see FIG. 2( c)) of the frame coupled body13 are respectively fitted into an intercell separation through hole 16of the separator member coupled body 10 so as to be closely contactedtogether.

Either of the openings 12 b and the openings 13 b of the frame coupledbodies 12 and 13 disposed on the front and back sides of the separatormember coupled body 10 each have a shape into which a membrane electrodeassembly (MEA) of the fuel cell is fitted.

The separator member coupled body 10 having the metal plate as the basebody may be provided with a protective layer (not shown) in the form ofan anticorrosive (weak acid resistant) and electrically conductive resinlayer, at least on a surface portion of the base body that will be onthe side of the electrolyte of the fuel cell.

There is no particular limitation about the separator member coupledbody 10 as long as it can bear the use of fuel, is anticorrosive (weakacid resistant) and electrically conductive, and has a predeterminedstrength.

The separator member coupled body 10 is obtained by processing a metalbase body into a predetermined shape through mechanical processing andetching processing using the photolithography technology and, in thisexample, the through holes 15 for fuel feeding or oxygen feeding and theintercell separation through hole 16 were formed by the use of thesemethods.

The intercell separation through hole 16 is provided in the form of aslit between the unit cells, and is configured such that joiningportions (corresponding to A7 and A8 shown in FIG. 2( b)) are cut offupon fabricating the fuel cell.

In this example, the portions A7 and A8 are removed upon fabricating thefuel cell, so that the separator members 10 a and 10 b of the separatormember coupled body 10 are separated for the respective unit cells.

As a material of the metal base body used for the separator membercoupled body 10, such a one is preferable that is excellent inelectrical conductivity, can obtain a predetermined strength, and isexcellent in processability, and there can be cited stainless steel,cold rolled steel, aluminum, or the like.

Further, as a method of disposing the acid-resistant and electricallyconductive resin film onto the surface portion of the metal base body,there can be cited a method of forming a film through electrodepositionusing a material composed by mixing a conductive material such as carbonparticles or anticorrosive metal into resin, and heating to cure it, ora method of forming, through electrolytic polymerization, a film in thestate wherein resin made of conductive polymers includes dopants thatenhance conductivity, and so forth.

In the present invention, plating processing such as gold plating may beapplied to the surface of the metal plate being the base body of theseparator member coupled body 10 so as to provide an anticorrosive metallayer without impairing conductivity of the separator surface.

Further, in the present invention, the separator member coupled body 10may also be configured that an acid-resistant and electricallyconductive resin film is further disposed on the anticorrosive metallayer.

As a method of disposing the anticorrosive metal layer such as the goldplating layer, a usual plating processing method can be used, anddetails are omitted herein.

The foregoing electrodeposition is carried out in the state whereanionic or cationic synthetic resin having an electrodepositing propertyis used as an electrodeposition liquid for electrodepositing a resinfilm, and a conductive material is dispersed in the electrodepositionliquid.

Although resin itself of the resin film formed by electrodeposition hasno conductivity, because the film is formed in the state where theconductive material is mixed in the resin, the resin film exhibitsconductivity.

As the anionic synthetic resin to be used, acrylic resin, polyesterresin, maleic oil resin, polybutadiene resin, epoxy resin, polyamideresin, polyimide resin or the like can be used alone or as a mixture inoptional combination of these resins.

Further, the foregoing anionic synthetic resin and cross-linking resinsuch as melamine resin, phenol resin or urethane resin may be usedjointly.

As the cationic synthetic resin, acrylic resin, epoxy resin, urethaneresin, polybutadiene resin, polyamide resin, polyimide resin or the likecan be used alone or as a mixture in optional combination of them.Further, the foregoing cationic synthetic resin and cross-linking resinsuch as polyester resin or urethane resin may be used jointly.

Further, for giving viscosity to the foregoing resin, it is possible toadd viscosity giving resin such as rosin, turpentine or petroleum resinif necessary.

The foregoing resin is subjected to an electrodeposition method in thestate where it is neutralized by an alkaline or acid substance to besoluble in water, or in the state of water dispersion. Specifically, theanionic synthetic resin is neutralized by amine such as trimethylamine,diethylamine, dimethylethanolamine or diisopropanolamine, or inorganicalkali such as ammonia or potassium hydroxide. The cationic syntheticresin is neutralized by acid such as acetic acid, formic acid, propionicacid or lactic acid. Then, the resin neutralized to be soluble in wateris used as a water dispersion type or a soluble type in the state whereit is diluted with water.

In case of the resin film formation using electrodeposition, there canbe cited carbon particles, anticorrosive metal or the like as aconductive material to be mixed in the resin, but not limited thereto aslong as an acid-resistant and electrically conductive resin layer can beobtained.

Basically, electrolytic polymerization is a method wherein electrodesare immersed in an electrolytic solution containing aromatic compoundsas monomers, thereby to perform polymerization through electrochemicaloxidation or reduction. Since this method is well known, details areomitted herein.

Conductive polymers can be synthesized directly into a film shape byelectrolytic polymerization, but, in this example, are in the statewhere the electrolytically polymerized resin contains dopants thatincrease conductivity.

For achieving the state where the electrolytically polymerized resincontains therein dopants that further increase conductivity, a method ofelectrochemical doping wherein dopants are contained upon electrolyticpolymerization, a method of liquid phase doping wherein, afterelectrolytic polymerization, conductive resin (polymer) formed throughthe electrolytic polymerization is immersed into a dopant liquid itselfor a solution containing dopant molecules, or the like can be used.

The dopants can be eliminated or neutralized by short-circuiting thecathode and the anode or applying a reverse voltage after thepolymerization, and further, it is possible to perform doping anddedoping reversibly by further controlling the voltage, thereby tocontrol the dopant concentration.

As donor-type dopants that give electrons, among dopants that are usedfor the resin film formation using electrolytic polymerization, therecan be cited alkali metal, alkylammonium ions or the like. Asacceptor-type dopants that snatch electrons, there can be cited halogen,Lewis acid, protonic acid, transition metal halide or organic acid.

As a material of the frame coupled bodies 12 and 13 arranged on thefront and back sides of the separator member coupled body 10, such a oneis preferable that is insulating, excellent in processability, light inweight, and large in mechanical strength. As such a material, asubstrate material for a printed wiring board, or the like is used. Forexample, glass epoxy, polyimide or the like is used.

Formation of the frame coupled bodies 12 and 13 having a desired shapecan be achieved by mechanical processing, laser processing or the like.

As a method of fabricating the separator 20 of this example, there canbe cited a method wherein the separator member coupled body 10 and theframe coupled bodies 12 and 13 individually fabricated according to theforegoing methods or the like are joined together under pressure whilepositioning them, thereby fabricating it.

For example, there are a method of applying an adhesive such as epoxyresin and curing the adhesive while the respective parts are overlapped,thereby fixing them together, and so forth.

There is no particular limitation about the adhesive used in this caseas long as it causes no influence onto other members in the fabricationprocess and, when employed in the fuel cell, it is excellent inresistance against an operating condition thereof.

Alternatively, there is also a method of forming part of or the whole ofthe frame coupled bodies by prepreg in a half-cured state, and joiningthem under pressure, thereby fixing them together.

As shown in FIGS. 1 and 2, the separator 20 of the first example is aseparator for fabricating a fuel cell provided with two unit cells,while a separator for fabricating a fuel cell provided with three ormore unit cells is similar thereto.

Specifically, as one similar to the first example, there can be cited aseparator having a further separator member (corresponding to 10 a, 10 bin FIG. 1) for fabricating a fuel cell provided with three or more unitcells with the structure like the first example.

As a modification of the separator 20 of the first example, there can becited one, as shown in FIG. 3, using a separator member coupled body 11provided with groove portions 17 that are formed by half etching so asto be perpendicular to the through holes 15, instead of the separatormember coupled body 10.

In this case, fuel or oxygen is fed in directions along the separator20, and fed from fuel feed grooves or oxygen feed grooves 17 a.

Also in case of this modification, portions B7 and B8 are removed uponfabricating a fuel cell, so that separator members 11 a and 11 b of theseparator member coupled body 11 are separated for the respective unitcells.

Further, in the first example and the modification of the foregoingembodiment, there can be cited a mode in which the separator membercoupled body is divided for the respective unit cells.

For example, it is the one in which A7 and A8 in FIGS. 1 and 2 areremoved, the one in which B7 and B8 in FIG. 3 are removed, or the like.

Further, as another modification, there can also be cited one whereinthe separator member coupled body 10 is not provided with theanticorrosive metal layer of gold plating or the like, but is providedwith only the protective layer in the form of the anticorrosive andelectrically conductive resin coating layer.

Further, in this example, the frame coupled body 12 is provided with theprojecting portion 12 c, and the frame coupled body 13 is provided withthe projecting portion 13 c. As a modification, however, it may also beconfigured that these projecting portions are not provided. In thiscase, for example, a member of the same material as that of the framecoupled bodies 12 and 13 is fitted into the intercell separation throughhole 16 of the separator member coupled body 10, and the separatormember coupled body 10 in this state is sandwiched by the frame coupledbodies 12 and 13 from both sides thereof so that the separator 20 isobtained.

Next, a second example of an embodiment of a separator for a flat-typepolymer electrolyte fuel cell of the present invention will be cited.

In the second example, the frame coupled body on the fuel feed side orthe oxygen feed side is replaced with a solid one. A plan view thereofis the same as FIG. 1( a), a sectional view corresponding to A3-A4-A5-A6of FIG. 1( a) becomes the same as FIG. 1( c), while a sectional viewcorresponding to A1-A2 of FIG. 1( a) becomes like FIG. 4. FIG. 12 is adiagram showing respective members in FIG. 4 in positions that arespaced apart from each other.

As shown in FIG. 4, a separator 120 of the second example has aseparator member coupled body 110 having a metal plate as a base body, aplate member 112 of a flat-plate shape disposed on one side of theseparator member coupled body 110, and a frame coupled body 113 disposedon the other side of the separator member coupled body 110.

The plate member 112 is made of an insulating material. The framecoupled body 113 is made of an insulating material, and comprises frameportions for giving insulation between unit cells, which are integrallycoupled to each other. The frame coupled body 113 has openings for fuelfeeding or oxygen feeding, corresponding to separator members,respectively.

When the separator 120 of this example is applied to the fuel cell, thesolid plate member 112 is subjected to processing so as to be formedwith openings for fuel feeding or oxygen feeding.

With respect to the frame coupled body 113 and the solid plate member112, the same material as that of the frame coupled bodies 12 and 13 inthe first example is applicable. With respect also to the separatormember coupled body 110, the same material as that of the separatormember coupled body 10 of the first example is applicable.

Also as a modification of the second example, there can be cited onelike the foregoing modification (see FIG. 3) of the first example.

Next, a third example of an embodiment of a separator for a flat-typepolymer electrolyte fuel cell of the present invention will be cited.

In the third example, a conductive layer of copper foil or the like isfurther disposed on the whole surface of the solid plate member of theseparator in the second embodiment. A plan view thereof is the same asFIG. 1( a), a sectional view corresponding to A1-A2 of FIG. 1( a)becomes like FIG. 5( a), and a sectional view corresponding toA3-A4-A5-A6 of FIG. 1( a) becomes like FIG. 5( b).

As shown in FIG. 5, a separator 125 of the third example has a separatormember coupled body 110 having a metal plate as a base body, a framecoupled body 113 disposed on one side of the separator member coupledbody 110, and a stacked base member comprising a plate member 112 of aflat-plate shape and a conductive layer 130 that are disposed on theother side of the separator member coupled body 110 in the order named.The conductive layer 130 is used for providing electrical connectionwhen the separator of this example is offered for fabrication of thefuel cell, and is removed depending on necessity. Like in the secondexample, the solid plate member 112 is subjected to processing so as tobe formed with openings for fuel feeding or oxygen feeding.

Copper foil or the like can be cited as the conductive layer 130 which,however, is not limited thereto.

Particularly, a one-side coppered substrate or the like can be cited asthe stacked base member in the combination of the solid plate member 112and the conductive layer 130.

The respective members other than the conductive layer 130 are basicallythe same as those of the second example.

Also as a modification of the third example, there can be cited one likethe foregoing modification (see FIG. 3) of the first example.

Next, a fourth example of an embodiment of a separator for a flat-typepolymer electrolyte fuel cell of the present invention will be cited.

A separator 20 a for a flat-type polymer electrolyte fuel cell of thefourth example is formed by disposing sealing members in the separator20 shown in FIG. 1. Specifically, as shown in FIG. 13, for enhancingairtightness of unit cells upon employment in the polymer electrolytefuel cell, sealing members 18 a and 18 b are provided so as to surroundthe openings 12 b and 13 b of the frame coupled bodies 12 and 13.

The sealing member 18 b is for sealing between the respective layersforming the separator 20 a, while the sealing member 18 a is for sealingbetween the separators 20 a mutually upon assembly into the fuel cell.

In the fourth example, each of the sealing members 18 a and 18 b is ofthe type wherein a grooving process is applied to the frame coupledbodies 12 and 13, and an O-ring is fitted thereinto. For the O-ring,there is used fluoro rubber or the like that is sufficient in gassealing property, moisture resistance, heat resistance, acid resistance,elasticity, and so on under the operating condition of the fuel cell.

The sealing members 18 a and 18 b may be formed by applying a liquidsealing agent onto the frame coupled bodies 12 and 13 by the use of adispenser or screen printing. In this case, for example, the liquidsealing agent is applied onto grooved portions and cured so that thesealing members 18 a and 18 b can be formed.

As the liquid sealing agent, there is preferably used vulcanizate ofperfluoro rubber, vulcanizate of liquid perfluoro rubber added with PTFE(abbreviation of polytetrafluoroethylene) fine powder as described inLaid-open Unexamined Patent Publication No. 2000-12054, and isobutyleneseries copolymer as described in Laid-open Unexamined Patent PublicationNo. 2001-325972, or the like.

The respective members other than the sealing members 18 a and 18 b arethe same as those of the separator 20 of the first example shown in FIG.1, and thus description thereof is omitted herein.

A method of fabricating the separator 20 a of the fourth example is alsobasically the same as the case of the first example, and there can becited a method wherein the separator member coupled body 10 and theframe coupled bodies 12 and 13 that are individually fabricated arejoined together under pressure while positioning them, therebyfabricating it.

Of course, such a one having a structure wherein the sealing members areprovided in the separator of the second example shown in FIG. 4 or ofthe third example shown in FIG. 5 can also be cited as one embodiment ofa separator for a flat-type polymer electrolyte fuel cell of the presentinvention.

Next, a first example of an embodiment of a fuel cell of the presentinvention will be described based on FIG. 6.

For convenience' sake, electrical connection is omitted in FIGS. 6( a)and 6(b) and is shown only in FIG. 6( c).

This example is a flat-type polymer electrolyte fuel cell having unitcells arranged in a flat manner, wherein the separators (correspondingto 21 and 22 in FIG. 6( a)) for the flat-type polymer electrolyte fuelcell of the first example shown in FIG. 1 are used on both the fuelfeeding side and the oxygen feeding side. Further, membrane electrodeassemblies (MEAs) 30 of the fuel cell are disposed so as to be fittedinto openings of frame portions (12A, 12B) of one of frame coupledbodies arranged on the front and back sides of each of separator membercoupled bodies 10A and 10B.

Of course, in this example, the joining portions A7 and A8 of theseparator member coupled body 10 of the separator 20 shown in FIG. 1 areremoved, thereby being separated for the respective unit cells.

Therefore, in this case, the separator 21, using the frame coupledbodies 12A and 13A, sandwiches such ones (also referred to as aseparator group) 10A that are in the state where the separator membercoupled body is divided for the respective unit cells, while theseparator 22, using the frame coupled bodies 12B and 13B, sandwichessuch ones (also referred to as a separator group) 10B that are in thestate where the separator member coupled body is divided for therespective unit cells.

A combined thickness of the frame coupled bodies 12A and 12B between theones (also referred to as separator groups) 10A and 10B each in thestate where the separator member coupled body is divided for therespective unit cells, is substantially equal to a thickness of themembrane electrode assembly (MEA) 30 so that the MEA can be provided ina flat manner.

In this example, at a portion C0 separating the unit cells from eachother, which corresponds to the region of the intercell separationthrough hole portion 16 in FIG. 2( b), only the frame coupled bodiesexist while being closely contacted with each other.

The number of the unit cells is set to two. On the other hand, as onesimilar to this example, there can be cited a fuel cell that is providedwith three or more unit cells with a structure like this example, byincreasing a separator member (corresponding to 10 a, 10 b in FIG. 1).

Herein, the frame coupled bodies 12A and 13A and the frame coupledbodies 12B and 13B, respectively, not only insulate the respective unitcells at portions other than connecting portions of the separatormembers, but also, simultaneously, serve as sealing members forpreventing fuel, moisture etc. inside the cells from leaking out to theexterior of the cells from portions other than the fuel feed surfaceswhile sandwiching the MEAs.

As methods for closely contacting and retaining the separators 21 and22, there can be cited the following methods. First, there is a methodof using an insulating adhesive between the respective members.Secondly, there is a method wherein part of or the whole of the framecoupled bodies 12A and 12B is formed from resin in a half-cured statesuch as prepreg and, after overlapping the respective members,thermo-compression bonding is applied thereto in a lump. Further,thirdly, there can be cited a method wherein the respective layers arestacked, then mechanically retained from the external by the use of ahousing 50 as shown in FIG. 7, or the like.

In the first method, in the state where an adhesive such as epoxy resinis applied and the respective members are overlapped with each other,the adhesive is cured. There is no particular limitation about theadhesive used in this case as long as it causes no influence onto othermembers in the fabrication process, and it is excellent in resistanceagainst an operating condition of the fuel cell. Further, instead of theadhesive, a resin sheet in a half-cured state such as prepreg that isused in a printed board, may be inserted.

In the second method, by replacing part of or the whole of the framecoupled bodies 12A and 12B with resin sheets in a half-cured state suchas prepreg, it is possible to further simplify the process. That is, thefuel cell is fixed by performing thermo-compression bonding in the statewhere the respective members are overlapped with each other. In thiscase, there is no particular limitation about the used resin sheet inthe half-cured state as long as it causes no influence onto othermembers in the fabrication process, and it is excellent in resistanceagainst an operating condition of the fuel cell.

The third method is the easiest and simplest method, wherein the cellbody may be assembled using a construction body such as the housing 50for fixing and retaining the fuel cell.

One example of a fabricating method of the fuel cell in this examplewill be briefly described.

First, with respect to two separators each being the same as theseparator 20 shown in FIG. 1, the joining portions A7 and A8 (see FIG.2( b)) of the respective separator member coupled bodies 10 are removedso as to prepare the separators 21 and 22 that are divided for therespective unit cells.

Further, the membrane electrode assemblies (MEAs) 30 are prepared.

Then, the membrane electrode assemblies (MEAs) 30 are placed on theopenings of the frame coupled body 12A of the separator 21.Subsequently, the separator 22 is overlapped over the separator 21 sothat the frame coupled body 12B of the separator 22 is positioned overthe membrane electrode assemblies (MEAs) 30, then they are joinedtogether under pressure. This enables the separator 21 and the separator22 to sandwich the membrane electrode assemblies (MEAs) 30 therebetweenin a fitted manner.

As a method of retaining the membrane electrode assemblies (MEAs)between the separators 21 and 22, the foregoing first to third methodsare adopted.

Then, electrical connection of the separator members is carried out forconnecting the unit cells in series, thereby fabricating the fuel cell.

In the fuel cell of this example, the electrical connection of theseparator members is performed using a filled via forming method thatuses conductive paste and is known as a wiring board fabricatingtechnology, and the connection is achieved as shown in FIG. 6( c).

In this example, the joining portions A7 and A8 are removed in advanceso that the separators 21 and 22 that are divided for the respectiveunit cells are used. On the other hand, if the separator 20, as shown inFIG. 1, having the frame coupled body 10 whose joining portions A7 andA8 are not removed is used, the joining portions A7 and A8, for the unitcells, of the frame coupled body 10 may be finally cut off so that thepolymer electrolyte fuel cell of this example can be obtained.

Herein, the electrical connection of the separator members between theunit cells in the fuel cell of this example will be described based onFIG. 8.

FIG. 8 shows process sectional views taken along C3-C4-C5-C6-C7 in FIG.6.

The separator 21 and the separator 22 are overlapped so as to sandwichtherebetween the membrane electrode assemblies (MEAs) 30, and joinedtogether under pressure, so that the membrane electrode assemblies(MEAs) 30 are fitted therebetween (FIG. 8( a)). Thereafter, by the useof a drill or laser irradiation, a through hole 45 is formed betweenC5-C6, and hole portions 46 for connection to the separator members areformed in the frame coupled bodies 13A and 13B (FIG. 8( b)).

Then, by the use of a dispenser or a printing method such as screenprinting, conductive paste is filled in the through hole 45 and the holeportions 46 thereby to form filled vias 41 and 42 (FIG. 8( c)).Thereafter, by the use of the dispenser or the printing method, wiring43 is further formed using the conductive paste (FIG. 8( d)).

For example, in case of the filling into the through hole 45, theconductive paste is applied using the screen printing or the like and,by disposing an aspirator on the opposite side of the substratesubjected to the hole processing to perform pressure reduction, theconductive paste can be filled into the through hole 45.

Thereafter, processes such as drying and burning are carried outdepending on necessity, and the electrical connection between theseparator members is completed.

As the conductive paste, silver paste, copper paste, gold paste,palladium paste, palladium-silver paste or the like may be cited.

As a first modification of the fuel cell in this example, there can becited one wherein electrical connection of the separator members betweenthe unit cells is implemented using bumps (also referred to asprojecting electrodes) as shown in FIG. 9( c).

FIG. 9 shows process sectional views in positions corresponding toC3-C4-C5-C6-C7 in FIG. 6.

Hereinbelow, the electrical connection of the separator members betweenthe unit cells in the fuel cell of this first modification will bebriefly described based on FIG. 9.

In case of the first modification, as different from the case of thefuel cell in the example of the embodiment shown in FIG. 6, theseparator 120 (see FIG. 4) of the second example provided with the solidplate member 112 on one side of the separator member coupled body 110 isused on both the fuel feed side and the oxygen feed side. In thisexample, membrane electrode assemblies (MEAs) 30 of the fuel cell aredisposed so as to be fitted into openings of a frame coupled body 113Aof a used separator 121 and a frame coupled body 113B of a usedseparator 122.

Hereinbelow, the electrical connection of the separator members betweenthe unit cells in this fuel cell will be briefly described based on FIG.9.

With respect to two separators each being the same as the separator 120shown in FIG. 4, the joining portions A7 and A8 (see FIG. 2( b)) of therespective separator member coupled bodies 110 are removed in advance soas to prepare the separators 121 and 122 that are divided for therespective unit cells.

Further, the membrane electrode assemblies (MEAs) 30 are also preparedin advance.

Then, the separator 121 and the separator 122 are overlapped so as tosandwich therebetween the membrane electrode assemblies (MEAs) 30, andjoined together under pressure, so that the membrane electrodeassemblies (MEAs) 30 are fitted therebetween. Thereafter, copper foils61 formed with conductive bumps 62 and 63 are prepared (FIG. 9( a)), andstacked on both sides thereof (FIG. 9( b)).

As a method of overlapping, closely contacting and retaining thesemembers, the same method as that in the foregoing example of theembodiment is applicable.

As the bump 62 or 63, one obtained by printing conductive paste aplurality of times to form it into a bump, a wire bump, one obtained byfurther coating the wire bump with conductive paste, or the like may beapplied.

Upon forming the bump, it is necessary to ensure a predetermined heightof the bump portion and sharpen its tip.

Thereafter, the copper foils 61 are etched by a photoetching method toform wiring 61 a, and the electrical connection between the separatormembers is completed (FIG. 9( c)).

Finally, the solid plate members 112A and 112B are formed with openingsfor fuel feeding and openings for oxygen feeding (not shown),respectively.

As a method of forming the opening portions, there can be cited a methodusing a carbon dioxide gas laser, a method by the use of mechanicalprocessing, or the like.

By this, it becomes unnecessary to protect the fuel feed portion fromthe external environment during the fabrication process, so that thedegree of freedom of the fabrication process is increased and handlingis also facilitated.

As a second modification of the fuel cell of this example, there can becited one wherein electrical connection of separator members betweenunit cells is implemented using plated through holes as shown in FIG.10( d).

FIG. 10 also shows process sectional views in positions corresponding toC3-C4-C5-C6-C7 in FIG. 6.

In case of the second modification, as different from the case of thefuel cell in the example of the embodiment shown in FIG. 6, theseparator 125 (see FIG. 5) of the third example provided with the solidplate member 112 and the conductive layer 130 in the form of copper foilas shown in FIG. 5 on one side of the separator member coupled body 110is used on both the fuel feed side and the oxygen feed side. In thisexample, membrane electrode assemblies (MEAs) 30 of the fuel cell aredisposed so as to be fitted into openings of a frame coupled body 113Aof a used separator 126 and a frame coupled body 113B of a usedseparator 127.

As a stacked base member comprising the solid plate member 112 and theconductive layer 130 in the form of the copper foil, a one-side copperedglass epoxy substrate or the like is applicable.

Hereinbelow, the electrical connection of the separator members betweenthe unit cells in this fuel cell will be briefly described based on FIG.10.

With respect to two separators each being the same as the separator 125shown in FIG. 5, the joining portions A7 and A8 (see FIG. 2( b)) of therespective separator member coupled bodies 110 are removed in advance soas to prepare the separators 126 and 127 that are divided for therespective unit cells.

Further, the membrane electrode assemblies (MEAs) 30 are also preparedin advance.

Then, the separator 126 and the separator 127 are overlapped so as tosandwich therebetween the membrane electrode assemblies (MEAs) 30, andjoined together under pressure, so that the membrane electrodeassemblies (MEAs) 30 are fitted therebetween. Thereafter, copper foils65 are stacked on both sides thereof (FIG. 10( a)).

As a method of overlapping, closely contacting and retaining thesemembers, the same method as that in the foregoing example of theembodiment is applicable.

Then, at portions where connecting portions are formed, vias 42A and athrough hole 45A for forming a through hole connecting portion areperforated by the use of a drill or a laser (FIG. 10( b)).

Then, after performing a desmear process and a catalyst applyingprocess, electroless plating is applied to the whole surface includingsurface portions of the via portions 42A and the through hole portion45A thereby to fill the through holes with a plating layer 70, so thatthe front and the back become electrically connectable (FIG. 10( c)).

As the electroless plating, electroless nickel plating, electrolesscopper plating or the like is suitably performed.

The electroless plating is performed using a prescribed plating liquid,after carrying out an activation process with a catalyst. Normally,copper plating is implemented.

Then, resist photoengraving is performed on the whole front and backsurfaces, and plating layer portions exposed from the resist is etchedusing a ferric chloride liquid or the like as an etching liquid to formconnection wiring 43 a. Thereafter, removal of the resist, and acleaning process if necessary, are carried out, thereby to obtain thepolymer electrolyte fuel cell of this example.

Herein, the through hole is filled with the plating layer, but notlimited thereto. For example, an ordinary through hole connectingportion may be formed such that the through hole may be formed to belarge and, when the front and the back are made electrically connectableby the plating, the through hole still penetrates through between thefront and the back.

Then, by the use of the photoetching method, the plating layer 70 andthe copper foils 65 are etched into predetermined shapes to form thewiring portion 43 a, and the electrical connection between theseparators is completed (FIG. 10( d)).

Finally, the solid plate members 112A and 112B are formed with openingsfor fuel feeding and openings for oxygen feeding (not shown),respectively.

As a method of forming the opening portions, there can be cited a methodusing a carbon dioxide gas laser, a method by the use of mechanicalprocessing, or the like.

By this, it becomes unnecessary to protect the fuel feed portion fromthe external environment during the fabrication process, so that thedegree of freedom of the fabrication process is increased and handlingis also facilitated.

Next, a second example of an embodiment of a fuel cell of the presentinvention will be described based on FIG. 14.

For convenience'sake, it is shown without electrical connection.

The second example is also a flat-type polymer electrolyte fuel cellhaving unit cells arranged in a flat manner. In this example, separators21 a and 22 a of the flat-type polymer electrolyte fuel cell of thefourth example shown in FIG. 13 are used on both the fuel feed side andthe oxygen feed side. Like in the first example, membrane electrodeassemblies (MEAs) 30 of the fuel cell are disposed so as to be fittedinto openings of one (12A, 12B) of frame coupled bodies arranged on thefront and the back of each of separator member coupled bodies 10A and10B.

Further, separator members between unit cells are electrically connectedthrough the foregoing filled via connection shown in FIG. 8.

Also in this second example, like the case of the first example, joiningportions

(corresponding to the portions A7 and A8 in FIG. 2) of the separatormember coupled body 10 of the separator 20 a shown in FIG. 13 areremoved, thereby being separated for the respective unit cells.

As described above, this example is configured to use the separators 20a (corresponding to 21 a and 22 a in FIG. 14) of the fourth example inthe flat-type polymer electrolyte fuel cell of the first example shownin FIG. 6, instead of the separators 20 of the first example. Sealingmembers 18 b seal between the respective layers of the separators 21 aand 22 a, while sealing members 18 a seal between the separators 21 aand 22 a mutually. Accordingly, as compared with the case of theflat-type polymer electrolyte fuel cell of the first example shown inFIG. 6 wherein no sealing members are provided, airtightness of the unitcells is improved.

The respective members other than the separators 20 a are basically thesame as those of the flat-type polymer electrolyte fuel cell of thefirst example, and a fabricating method is also basically the same.

As a modification of the flat-type polymer electrolyte fuel cell of thesecond example, there can be cited one wherein electrical connection ofthe separator members between the unit cells is implemented by theforegoing bump connection shown in FIG. 9, or the foregoing through holeconnection shown in FIG. 10.

Of course, a flat-type polymer electrolyte fuel cell using such a onehaving a structure wherein the sealing members are provided in theseparator of the second example shown in FIG. 4 or of the third exampleshown in FIG. 5 can also be cited as one of flat-type polymerelectrolyte fuel cells of the present invention.

INDUSTRIAL APPLICABILITY

As described above, a separator of the present invention can be used ina flat-type polymer electrolyte fuel cell, and the flat-type polymerelectrolyte fuel cell using the separator of the present invention canrealize reduction in weight, improvement in strength, and further,improvement in airtightness of each unit cell.

1. A separator for a flat polymer electrolyte fuel cell having unitcells arranged in a flat manner, said separator provided on a fuel feedside or an oxygen feed side, said separator comprising: a separatormember coupled body having a metal plate as a base body, and formed byintegrally coupling a plurality of separator members each having throughholes for feeding fuel to an electrolyte of the fuel cell, said throughholes arranged so as to correspond to the unit cell and to beperpendicular to a surface of said base body so that the through holesextend from a front side of the separator member coupled body to a backside of the separator member coupled body, a frame coupled body made ofan insulating material, having openings for fuel feeding or oxygenfeeding corresponding to the respective separator members, and formed byintegrally coupling a plurality of frame members that give insulationbetween the unit cells, and a solid plate member made of an insulatingmaterial, wherein said frame coupled body and said solid plate member,making a pair, sandwich said separator member coupled body on therespective front side and back side, and a membrane electrode assemblyof a respective unit cell fits into said opening of each respectiveframe member, wherein the solid plate member includes a first projectingportion, the framed coupled body includes a second projection portion,and the separator member coupled body includes an intercell separationthrough hole, and wherein when the frame coupled body and the solidplate member sandwich the separator member coupled body, the firstprojection portion and the second projection portion are respectivelyfit into the intercell separation through hole so that the firstprojection portion and the second projection portion contact.
 2. Aseparator for a polymer electrolyte fuel cell according to claim 1,wherein said frame coupled body and said solid plate member are providedwith grooves, and an O-ring is disposed in said grooves as a sealingmember.
 3. A separator for a polymer electrolyte fuel cell according toclaim 1, wherein sealing members, disposed by a dispenser, are provided(1) between the separator member coupled body and the frame coupled bodyforming the separator, (2) between the separator member coupled body andthe solid plate member, (3) on a surface of the frame coupled body, and(4) on a surface of the solid plate member.
 4. A separator for a polymerelectrolyte fuel cell according to claim 1, wherein sealing members,disposed by printing, are provided (1) between the separator membercoupled body and the frame coupled body forming the separator, (2)between the separator member coupled body and the solid plate member,(3) on a surface of the frame coupled body, and (4) on a surface of thesolid plate member.
 5. A separator for a polymer electrolyte fuel cellaccording to claim 1, wherein the separator member has, on one surfacethereof, a groove portion communicating with said through holes.
 6. Aseparator for a polymer electrolyte fuel cell according to claim 5,wherein said groove portion is formed by half etching.
 7. A separatorfor a polymer electrolyte fuel cell according to claim 1, wherein theseparator member has an anticorrosive metal layer that does not impairconductivity of the surface thereof.
 8. A separator for a polymerelectrolyte fuel cell according to claim 1, wherein the separator memberhas a weak acid resistant and electrically conductive resin coating filmon at least a surface that will be on the side of the electrolyte of thefuel cell.
 9. A separator for a polymer electrolyte fuel cell accordingto claim 8, wherein said resin coating film is a resin coating filmformed by electrodeposition, electrolytic polymerization, or acombination of both.